The present invention relates to a paper discharging means for an offset printing machine.
In general, there is provided a means for discharging papers which removes printed papers from a rubber cylinder by means of a gripper, and draws them out onto a table which is arranged, for example, at the back of a printing machine. This device facilitates the after treatment of the printed papers in the offset printing machine.
In this discharging device, the table is provided in such a way as to fittedly engage a pair of rails which are longitudinally provided so as to be opposite to the insides of frames on either side of the printing machine proper, or frames on both sides of the device are fixedly mounted to the above-mentioned frames so as to be capable of being raised and lowered. The table is arranged so as to be lowered in its proper course by a drive chain which is provided around a sprocket of a sprocket shaft provided so as to be moved in conjunction with the driving of the printing machine.
However, the conventional discharge means is constructed such that the ratchet coupled to the sprocket shaft is always in engagement with the feed pawl which feeds the ratchet, so that the table is lowered without regard to whether papers are discharged or not.
Therefore, since the printing machine proper is driven in case the supply of paper is brought to a halt for some reason, the table continues to be lowered. Therefore, when printing is started again, the drop of the discharged paper to the table becomes longer than required. Hence, there is an inconvenience in that the direction and the like of the papers does not become uniform, thereby worsening the proper arrangement thereof.
In addition, a troublesome manual operation was required to return the table upwardly to correct for the excessive lowering in the midst of printing.